# Dos 攻击防范（自动屏蔽攻击 IP)
function ddos_shield(){
	# nginx access日志
	LOG_FILE=/usr/local/nginx/logs/demo2.access.log
	# nginx access日志中的时间格式
	DATE=$(date +%d/%b/%Y:%H:%M)
	# 检索异常IP
	ABNORMAL_IP=$(tail -n5000 ${LOG_FILE} |grep ${DATE} |awk '{a[$1]++}END{for(i in a)if(a[i]>10)print i}')
	# 记录过滤IP的清单
	DROP_IP_FILE=/tmp/drop_ip.log

	# 检查IP是否自爱iptables的允许通过清单中，否则过滤掉
	for IP in ${ABNORMAL_IP};do
		if [[ $(iptables -vnL |grep -c "$IP") -eq 0 ]]; then
			iptables -I INPUT -s $IP -j DROP
			echo "$(date +'%F_%T') $IP" >> /tmp/drop_ip.log
		fi
	done
}

# Nginx 访问日志分析
function nginx_log_analyse(){
	# 日志格式: $remote_addr - $remote_user [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent" "$http_x_forwarded_for"
	LOG_FILE=$1
	echo "统计访问最多的10个IP"
	awk '{a[$1]++}END{print "UV:",length(a);for(v in a)print v,a[v]}' $LOG_FILE |sort -k2 -nr |head -10
	echo "----------------------"

	echo "统计时间段访问最多的IP"
	awk '$4>="[01/Dec/2018:13:20:25" && $4<="[27/Nov/2018:16:20:49"{a[$1]++}END{for(v in a)print v,a[v]}' $LOG_FILE |sort -k2 -nr|head -10
	echo "----------------------"

	echo "统计访问最多的10个页面"
	awk '{a[$7]++}END{print "PV:",length(a);for(v in a){if(a[v]>10)print v,a[v]}}' $LOG_FILE |sort -k2 -nr
	echo "----------------------"

	echo "统计访问页面状态码数量"
	awk '{a[$7" "$9]++}END{for(v in a){if(a[v]>5)print v,a[v]}}'
}

# 查看网卡实时流量
function check_if(){
	NIC=$1
	echo -e " In ------ Out"
	while true; do
		OLD_IN=$(awk '$0~"'$NIC'"{print $2}' /proc/net/dev)
		OLD_OUT=$(awk '$0~"'$NIC'"{print $10}' /proc/net/dev)
		sleep 1
		NEW_IN=$(awk  '$0~"'$NIC'"{print $2}' /proc/net/dev)
		NEW_OUT=$(awk '$0~"'$NIC'"{print $10}' /proc/net/dev)
		IN=$(printf "%.1f%s" "$((($NEW_IN-$OLD_IN)/1024))" "KB/s")
		OUT=$(printf "%.1f%s" "$((($NEW_OUT-$OLD_OUT)/1024))" "KB/s")
		echo "$IN $OUT"
		sleep 1
	done
}

# 服务器系统配置初始化脚本
function init_os(){
	# 设置时区并同步时间
	ln -s /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
	if ! crontab -l |grep ntpdate &>/dev/null ; then
		(echo "* 1 * * * ntpdate time.windows.com >/dev/null 2>&1";crontab -l) |crontab
	fi

	# 禁用selinux
	sed -i '/SELINUX/{s/permissive/disabled/}' /etc/selinux/config

	# 关闭防火墙
	if egrep "7.[0-9]" /etc/redhat-release &>/dev/null; then
		systemctl stop firewalld
		systemctl disable firewalld
	elif egrep "6.[0-9]" /etc/redhat-release &>/dev/null; then
		service iptables stop
		chkconfig iptables off
	fi

	# 历史命令显示操作时间
	if ! grep HISTTIMEFORMAT /etc/bashrc; then
		echo 'export HISTTIMEFORMAT="%F %T `whoami` "' >> /etc/bashrc
	fi

	# SSH超时时间
	if ! grep "TMOUT=600" /etc/profile &>/dev/null; then
		echo "export TMOUT=600" >> /etc/profile
	fi

	# 禁止root远程登录
	sed -i 's/#PermitRootLogin yes/PermitRootLogin no/' /etc/ssh/sshd_config

	# 禁止定时任务向发送邮件
	sed -i 's/^MAILTO=root/MAILTO=""/' /etc/crontab

	# 设置最大打开文件数
	if ! grep "* soft nofile 65535" /etc/security/limits.conf &>/dev/null; then
		cat >> /etc/security/limits.conf << EOF
    * soft nofile 65535
    * hard nofile 65535
EOF
    fi

    # 系统内核优化
    cat >> /etc/sysctl.conf << EOF
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_max_tw_buckets = 20480
net.ipv4.tcp_max_syn_backlog = 20480
net.core.netdev_max_backlog = 262144
net.ipv4.tcp_fin_timeout = 20
EOF

    # 减少SWAP使用
    echo "0" > /proc/sys/vm/swappiness

    # 安装系统性能分析工具及其他
    yum install -y gcc make autoconf vim sysstat net-tools iostat if
}

# 监控 100 台服务器磁盘利用率脚本
function monitor_host_df(){
	HOST_INFO=host.info
	for IP in $(awk '/^[^#]/{print $1}' $HOST_INFO); do
		USER=$(awk -v ip=$IP 'ip==$1{print $2}' $HOST_INFO)
		PORT=$(awk -v ip=$IP 'ip==$1{print $3}' $HOST_INFO)
		TMP_FILE=/tmp/disk.tmp
		ssh -p $PORT $USER@$IP 'df -h' > $TMP_FILE
		USE_RATE_LIST=$(awk 'BEGIN{OFS="="}/^\/dev/{print $NF,int($5)}' $TMP_FILE)
		for USE_RATE in $USE_RATE_LIST; do
			PART_NAME=${USE_RATE%=*}
			USE_RATE=${USE_RATE#*=}
			if [ $USE_RATE -ge 80 ]; then
				echo "Warning: $PART_NAME Partition usage $USE_RATE%!"
			fi
		done
	done
}